I posted this on the Super Duty Forum on this site, but following suggestions I am also posting it here for ideas.
Last Friday I was pulling our camper out for the weekend. It was 90 degrees outside, camper is a 30 foot travel trailer. Truck is a 2005 F350 with the 6.0. About 3 or 4 years ago I replaced the radiator and the oil cooler. That was somewhere around 20,000 and 30,000 miles ago. I was pulling along at 65mph and all was running fine but the oil temp started going up. It got up to 238 so I pulled over and let it idle for about 5 minutes and cool down. It came down to 225 so I took off again. It went back up and was hovering around the 230 to 235 range. When I backed down to 55mph and held the rpm's under 1800 it stayed cooler, still around 228 to 230. The water temp stayed 6 to 8 degrees lower than the oil temp, running between 228 and 232.
Today was cooler, only 70 degrees out. I pulled the camper home and the temp stayed around the 220 to 225 mark. When I got up to 65mph it would creep up to 225 when I backed down to 55mph it dropped to 221 to 223. It usually has always ran in that range even at 75 on the interstate. Today the water temp also stayed at about 216 to 220. Even driving empty without a trailer I have been thinking it has been running a little warmer than usual, between 208 and 212. Usually empty it didn't get above 205. The water temp has been staying less than 10 degrees cooler than the oil temp.
Back when I changed the oil cooler the dealer told me to run the green antifreeze so that is what I have had in it the past few years. It does have a slight leak around the transmission line at the radiator, but Friday it was not too low. It was showing on the minimum mark on the degas container.
So, what is everyones thoughts? I was suspecting the oil cooler again, but the water temp was staying right there in what I feel is a good range compared to the oil temp. I believe I was told once to keep the water temp within 12 degrees of the oil temp.
I am thinking about changing the coolant and flushing the system. Is there anything I should run in it to flush out the oil cooler? I have used different products over the years in cars that is supposed to flush the cooling system. In a few weeks we are going to go camping farther from home, I want to get this resolved before then. Also in July if the country is back open we are planning a trip pulling our smaller trailer to Colorado. Any ideas or advice would be appreciated!
Thanks in advance!

 

that does sound a little too hot. I have heard that at some point the pcm begins defueling in response to over heated oil.. I am just guessing but 238 is perhaps too hot. For reference, my 03 runs about 195-200 ECT with a 10-12 degree delta to the EOT at 70mph no trailer. And with my boat ( about 9,000-10,000 lbs) towing at 60-65 mph the ECT runs ,on flat ground, about 215 with an EOT about 220-222. on a bridge ramp the ECT goes up to 220+/- and oil 225-227. Mine has a new water pump, new radiator and about one year on the oil cooler. I think mine runs a little too hot , but I would be worried about 238 EOT. Since this apparently just happened maybe it is linked to some fault, fan speed?, water circulation? (damaged impeller?) dirty radiator fins? (bugs). I have changed my coolant to ELC-1 Cat spec, the red stuff. I dont think the coolant brand would cause this at least not in a short term.What about your belt, the tensioner and idler pulleys. Those are IMO, maintenance items that should be replaced every few years maybe around 100K. If they have been on your truck for a while, maybe just replace them. The water pump with it's plastic impeller don't last forever either.

 

Thanks for the input. I have a response on the super duty forum too that also mentions the fan speed. I have been doing a lot of reading about the cooling system and have a few ideas on where to start. I did not know that these have plastic impellers on the water pump. That adds another item to look into.
The next time I get a chance I am going to connect my laptop with forscan and see if I can get the fan speed to monitor. As soon as I can get to a parts store I am going to get the correct antifreeze and do a flush. I think I need to get the green universal stuff out of it. I was just reading a past post on here about Gooches flush procedure. When I pick up the antifreeze I will also get the flush valve and do a complete flush of the system. I am also thinking about just changing the water pump while I have the coolant drained.
The pickup has about 280,000 miles, and in the 5 years I have owned it I have not had to do any work to the water pump. The belt looked good the last time I checked it, but thinking back that was probably last summer.
I will post back as soon as I get time to look at it more.
Thanks!

 

If you go in to replace the water pump. it would be a good idea to replace the tensioner assby and the idlers. try Rock Auto. I have a diesel site billet water pump ( ~$225) also there is the Bullet Proof billet pump, (~$350). I order the Shell rotella ELC-- from Amazon, case of 6.
As for fan speed, you can put ForScan LITE on your cell phone and get a blue tooth obdII adaptor, the forscan download is a just a few bucks and and the BAFX blue tooth is about 25 on amazon. The forsacn is great for trouble shooting and can work as a monitor while driving too. Don't forget to use distilled water for the final flushes and to mix with the ELC.
The 6.0 EGR cooler puts the anti freeze through the ringer, the exhaust gas temperatures in the cooler can be well over 1000 degres, not a good place for minerals.

 

I am behind the times, I did not know there was a forscan for cell phones. I will have to look into that! I have a wifi adaptor that I got for my wifes Chevy that I use with dash command. I don't really like dash command so I will be looking for the forscan app.
I checked the water pump on Rock Auto, it is cheaper than I thought. I have to haul some stuff for an elderly couple today I will try to watch the fan speed while I am out.
Thanks again for the help!

 

Not many answers found today. I didn't have much weight in the pickup and it is in the high 60's today. I ran through some hills about 80mph but could only get the coolant temp up to 202 and the oil temp to 208. The fan speed hit 580 to 600 when it was that warm, but typically ran at 400 to 500. It did get a little over 600 at one time, but stayed around the 580 rpm range.

 

I just did my tensioner and both idlers and belt.
Got an OEM ford one off rock auto and two gates idler pulleys.
Stopped the squeak when shutting the truck off

 

The way I look at "water pump" health centers around the oil cooler. If you are seeing good temperature differentials between the oil temp and coolant temp, then I believe that this is telling you that you probably have a healthy water pump. Without good coolant flow, I believe that the coolant temperature will rise, but the oil temperature will rise even more ..... and you will see the temperature differential (delta if you will) noticeably increase.

If both the coolant and oil temperatures increase at the relatively same differential, then the issue is probably related to 1) the radiator's capability to remove heat (which includes fan operation) 2) excessive heat is being generated, or 3) the thermostat itself is not performing correctly.

Love to hear other's thoughts on this.

 

Agreed the oil cooler is meant to exchange heat between the oil and coolant.
Keep them together whether that be at 190 deg or 230.

If your deltas are good like you suggest I would focus on the cooling system...

Thermostat
Rad
Any coolant leaks
Fan
Water pump

 

As I mentioned in the post in the other forum, I think your issue is fan related. Since you mention being deleted, you probably don't have an EGR valve? When its unplugged the fan will not work (no good reason, but that's how Ford programmed it). The solution is install a "dummy" EGR valve that is mounted outside the engine or could be installed in the intake. With no EGR cooler there will be no flow, so no harm. Another option some guys do is convert to a mechanical clutch from the 7.3. You have to buy an adapter to mount it to the 6.0 water pump.

On my truck the fan typically won't start spooling up till about 207-210 ECT range. It will usually spool to about half engine rpm and then gradually increase the speed until full lockup around 218-220 at which point you will hear the fan VERY clearly.

 

That is what is baffling me. I was a mechanic back in the late 80's and early 90's. Now I don't work in a shop, but am well known in my town for repairing peoples cars, mowers, golf carts and whatever else they bring me to work on. It is a sideline income for me to support my kids auto racing addictions, but I don't do a lot of work with diesels. This is fairly new to me, I get the concept of the oil cooler and changed the oil cooler myself a few years ago.
What confuses me is this does not follow any patterns that I would typically see for heating issues. I don't have coolant in the oil and it still runs smooth so a head gasket or cracked head is almost ruled out. It does have a coolant drip in the radiator around the transmission cooling line, but due to laziness it has been dripping for a couple of years. I only lose about 1/4 of a gallon every 3 or 4 months. The coolant temp and water temp are consistently within 6 to 8 degrees of each other. When I was pulling the camper and the oil temp started rising it did rise faster than the water temp at first, but then the water temp would catch up to it within a few minutes but the numbers still stayed steady.
The radiator was new 3 or 4 years ago, and I don't drive this pickup in dirty conditions, by visual inspection it doesn't appear to be plugged. I will get the air out and blow the radiator and ac condenser out just to make sure.
It has been running a couple of degrees warmer than it used to, but it has been staying below 212 until I had the camper on the other day.

 

Don't rule out a head gasket leak just because there is no coolant in the oil. You could have hot combustion gas leaking into the coolant and since you have a slow coolant leak you may not see the degas bottle cap "spewing" coolant due to the pressure increase that would occur on a leak-free system.

 

I have been giving your other post a lot of thought. The EGR was deleted when I bought the pickup 5 or 6 years ago. I am going to do more research on the EGR delete, I will admit I don't know a lot about that process. When I had it apart changing the oil cooler I noticed it had a J pipe installed and was told that is the EGR delete. Other than that I honestly don't know much else. I will check into that along with the other suggestions here. I would think, and I may well be wrong, but if the EGR not sending a signal to the fan it would have showed itself by now? A final thought, last week when the temp did get above 225 I could hear a roaring sound that I suspect was the fan. That doesn't mean it was turning as fast as it should have been.

 

Again that points to the fan not working as you've got high ECTs. Fan running at low speeds basically becomes a choke point, restricting airflow thru the radiator. I always assumed the fan had no affect at freeway speed until I got into towing & started watching the engine. Pulling a hill in my truck in 100+ at 60mph temp my coolant will rise up to 220F, fan hits full speed and the coolant temp drops quickly to below 210. Fan unlocks, coolant rises back to 220F, fan comes back on etc. etc.

 

As much as I don't want to, I have to agree with that. That possibility is not at the top of my list because 1 it is expensive and 2 it only heated up when the outside temp was above 90 and I was pulling the camper. Coming home with the outside temps in the 70's it ran a little cooler. The oil and engine temp stayed below 230 most of the trip home.
Also it only did this with the camper on, the camper weighs in around 10,000 pounds.